Fuses have long been used in electrical devices for providing an interruptible electrical connection between a source of electrical power and a component in an electrical circuit that is to be protected. For example, upon the occurrence of an overcurrent condition in a circuit, such as may result from a short circuit or other sudden electrical surge, an element within in the fuse may separate and interrupt the flow of electrical current to a protected circuit component, thereby preventing or mitigating damage to the component that could otherwise result if the overcurrent condition were allowed to persist.
One type of fuse that is well known in the art includes a hollow fuse body and a fuse element disposed within the hollow body. For example, FIG. 1 illustrates a side view of a conventional fuse 100 having a hollow, tubular fuse body 110. The fuse 100 includes a first end cap 130, a second end cap 140, and a fuse element 120 disposed within, and extending through, a cavity 150 of the hollow fuse body 110 to form an electrical connection between the end caps 130 and 140. The fuse element 120 is formed of an electrically conductive material having a relatively low melting point. The end caps 130 and 140 are made from an electrically conductive material and fit over the longitudinal ends of the fuse body 110 to provide electrical contact with the fuse element 120. The fuse element 120 is connected to the end caps 130 and 140 by solder fillets 155, which are disposed at opposite ends of the fuse body 110. The cavity 150, defined by an interior surface 115 of the fuse body 110, contains an insulative filler 160 which may be a powdered or granular non-conductive material, such as a sand.
When the fuse element 120 melts or separates due to a predetermined, excessive amount of current flowing through the fuse element 120, an electric arc forms between the un-melted portions of the element. The arc grows in length as the separating portions of the fuse element 120 recede from each other until the voltage required to sustain the arc is higher than the available voltage in the protected circuit, thus terminating the current flow. It is therefore desirable to suppress such arcs as quickly as possible to limit the time after the excessive current is reached until current flow is arrested. The insulative filler material 160 acts to suppress the electrical arc in the exemplary conventional fuse 100 by filling the gap that forms between melted portions of the fuse element 120. However, because of limited surface area contact between the filler material 160 and the fuse element 120, the time required to quench an arc may be still be excessive (i.e. not sufficiently expedient to prevent damage to a protected circuit component). It is therefore apparent that a need exists to improve arc quenching in fuses.